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jms019@gmail.com: Mar 12 07:11AM -0700 I have partially repaired an IBM mono monitor whose mains transformer had failed.   http://minuszerodegrees.net/oa/OA%20-%20IBM%20Monochrome%20Display%20(5151).pdf   Driven from a genuine PC of the day which drives another such monitor perfectly well the picture now sort of moves around but at a rate of 1-2Hz. Turning up the brightness shows a wavy left/right edge implying a few hundred Hz effect. But the effect is also vertical.   Note I say moves. It does _not_ contract or expand which would indicate insufficient headroom after the rectifier before the 15v regulator. I am happy this isn't happening.   Now I notice the original transformer was a solid metal screened thing with an extra grounding wire.   I have twisted and moved the secondary wires away from the tube and also moved away and screened the transformer temporarily to no effect. Various things to try next include ferrites on primary/secondary wiring, a UPS and maybe some extra caps and also jumpering across from a working monitor.   The environment is terrible being a retro museum on an industrial estate with a railway depot over the road.   Though generally experienced this baffles me somewhat so I'd appreciate your thoughts.   Is the problem likely to be common mode noise ?   Ideally I'd like to keep this transformer and not have to seek out a screened one.   Thanks.

Pimpom <Pimpom@invalid.invalid>: Mar 12 09:41PM +0530 > http://minuszerodegrees.net/oa/OA%20-%20IBM%20Monochrome%20Display%20(5151).pdf   > Driven from a genuine PC of the day which drives another such monitor perfectly well the picture now sort of moves around but at a rate of 1-2Hz. Turning up the brightness shows a wavy left/right edge implying a few hundred Hz effect. But the effect is also vertical.   > Note I say moves. It does _not_ contract or expand which would indicate insufficient headroom after the rectifier before the 15v regulator. I am happy this isn't happening.   Did you check to see if the regulator does have sufficient headroom? Maybe the replacement transformer has a lower output voltage or lower current capacity.     > Though generally experienced this baffles me somewhat so I'd appreciate your thoughts.   > Is the problem likely to be common mode noise ?   > Ideally I'd like to keep this transformer and not have to seek out a screened one.   My first suspect after the power transformer would be a filter capacitor that had become dry or leaky.   Considering that signal levels in a monitor are much higher than in sensitive analog systems like audio amplifiers, I doubt that the symptoms are caused by stray fields from an unshielded transformer.

tabbypurr@gmail.com: Mar 12 09:12AM -0700 On Monday, 12 March 2018 14:11:49 UTC, Jon wrote:     > Is the problem likely to be common mode noise ?   > Ideally I'd like to keep this transformer and not have to seek out a screened one.   > Thanks.   Ferret beads aren't going to do anything at the frequency of interest. Have you checked all the psu rails for hum? Tried some grounded steel between trafo & tube? Put grounded steel over the whole monitor to see if it's an external field?     NT

Jon <jms019@gmail.com>: Mar 12 09:18AM -0700 I did try doubling up the 4700uF with another which yes I checked the capacitance of first.   Also what are R602 and D605 for ?   Jon

Jon <jms019@gmail.com>: Mar 12 09:30AM -0700 The 4700uF cap sits at 28V which given a measured consumption of 1.4A is fine giving a ripple of the order of a hundred millivolts. And as I said doubling it makes no difference.

captainvideo462009@gmail.com: Mar 11 07:41PM -0700 A friend of mine has a 120volt string of lights above his swimming pool. There is one 15 amp circuit for both the lighting and the pump motor circuit. This circuit is not protected by a GFCI outlet. The lights however are high enough so that no one can ever reach up and grab them while in the pool. We have had discussions about installing a GFCI on the pool circuit but as of the end of last Summer's swimming season it had not been done. One day last Summer I observed his kids in the pool shooting water blaster pistols in the air. Alarmed I quickly killed power to the lights. Naturally my concern was that someone in the pool shooting water up at the lights could be electrocuted. This brought about an interesting hypothetical discussion. What if the pool lighting circuit were connected through an isolation transformer. In theory then you should be able to grab each side of the secondary without being shocked right? I can't see how the motor could fail and become a shock hazard so I was more concerned about the lights.   In any event I'm going to install a GFCI on his pool circuit for him before the start of swimming season which will be coming up in a couple of months. Thanks, Lenny

John Robertson <spam@flippers.com>: Mar 11 08:25PM -0700 > A friend of mine has a 120volt string of lights above his swimming pool. There is one 15 amp circuit for both the lighting and the pump motor circuit. This circuit is not protected by a GFCI outlet. The lights however are high enough so that no one can ever reach up and grab them while in the pool. We have had discussions about installing a GFCI on the pool circuit but as of the end of last Summer's swimming season it had not been done. One day last Summer I observed his kids in the pool shooting water blaster pistols in the air. Alarmed I quickly killed power to the lights. Naturally my concern was that someone in the pool shooting water up at the lights could be electrocuted. This brought about an interesting hypothetical discussion. What if the pool lighting circuit were connected through an isolation transformer. In theory then you should be able to grab each side of the secondary without being shocked right? I can't see how the motor could fail and become a shock hazard so I was more concerned about the lights.   If you grabbed each side of the secondary you would receive a 100/115/120/220/240VAC shock (depending on where you live on Earth). If somehow one side of the secondary connected to earth ground then you would back to the same risk of electrical shock. Your decision to run GFCI is correct IMHO.     > In any event I'm going to install a GFCI on his pool circuit for him before the start of swimming season which will be coming up in a couple of months.. Thanks, Lenny   Best decision.   John :-#)#   -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 (604)872-5757 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out."

Mike Coon <gravity@mjcoon.plus.com>: Mar 12 09:18AM In article <Ao6dnUV3-ZCObjjHnZ2dnUU7-enNnZ2d@giganews.com>, spam@flippers.com says... > somehow one side of the secondary connected to earth ground then you > would back to the same risk of electrical shock. Your decision to run > GFCI is correct IMHO.   I would prefer "either" rather than "each". Certainly not "both"! We have road signs saying "Use both lanes" which appear to encourage straddling. Presumably the public are supposed not to understand "either"...   Mike.

"pfjw@aol.com" <peterwieck33@gmail.com>: Mar 12 05:48AM -0700 An isolation transformer does not guard against electrocution if one inserts one's self into the circuit. All it does is isolate the primary from the secondary such that for that circuit, the secondary side is isolated from ground. A GFCI device is the _only_ valid choice in this situation.   Peter Wieck Melrose Park, PA

Terry Schwartz <tschw10117@aol.com>: Mar 12 06:41AM -0700 > An isolation transformer does not guard against electrocution if one inserts one's self into the circuit. All it does is isolate the primary from the secondary such that for that circuit, the secondary side is isolated from ground. A GFCI device is the _only_ valid choice in this situation.   > Peter Wieck > Melrose Park, PA   Disagree. A much better choice is to remove the lighting and replace with a low voltage string, or a solar/battery powered string, or eliminate it all together.   By low voltage, I don't mean a modern string of LED lights. I mean a transformer isolated 12v system. The transformer should still be on a GFCI circuit.   120V above the pool area is just foolish and dangerous.   The pool pump motor may not like being on a GFCI. Often, inductive motor loads will trip them under a heavy load such as startup or near stall. In that case, the GFCI will work better back at the load center (circuit breaker panel) where the inductance of the wiring does not compound the problem. I just dealt with this last summer on a boat lift circuit.   Terry

"pfjw@aol.com" <peterwieck33@gmail.com>: Mar 12 06:54AM -0700 On Monday, March 12, 2018 at 9:41:38 AM UTC-4, Terry Schwartz wrote:     > 120V above the pool area is just foolish and dangerous.   > The pool pump motor may not like being on a GFCI. Often, inductive motor loads will trip them under a heavy load such as startup or near stall. In that case, the GFCI will work better back at the load center (circuit breaker panel) where the inductance of the wiring does not compound the problem. I just dealt with this last summer on a boat lift circuit.   > Terry   Of course. But if 120 VAC must be used, a GFCI devices is the only valid choice.   We feed our hot-tubs from a 50A GFCI safety switch in a dry location away from the hot-tub, but not near the main panel. It is easily reached from the outside as well.

Ralph Mowery <rmowery28146@earthlink.net>: Mar 12 10:20AM -0400 In article <a4bd1a14-82de-42bb-9284-bd1cda2cd11f@googlegroups.com>, captainvideo462009@gmail.com says...   > A friend of mine has a 120volt string of lights above his swimming pool. There is one 15 amp circuit for both the lighting and the pump motor circuit. This circuit is not protected by a GFCI outlet. The lights however are high enough so that no one can ever reach up and grab them while in the pool. We have had discussions about installing a GFCI on the pool circuit but as of the end of last Summer's swimming season it had not been done. One day last Summer I observed his kids in the pool shooting water blaster pistols in the air. Alarmed I quickly killed power to the lights. Naturally my concern was that someone in the pool shooting water up at the lights could be electrocuted. This brought about an interesting hypothetical discussion. What if the pool lighting circuit were connected through an isolation transformer. In theory then you should be able to grab each side of the secondary without being shocked right? I can't see how the motor could fail and become a shock hazard so I was more concerned about the lights.   > In any event I'm going to install a GFCI on his pool circuit for him before the start of swimming season which will be coming up in a couple of months. Thanks, Lenny   An isolation transformer would be safe up to a point. If there is a breakdown in the insulation anywhere in the circuit, one side of the circuit becomes grounded by accident and no one notices it. Then if someone gets on the other side of the line, he is shocked or worse. That is one reason most circuits are grounded.

John Robertson <spam@flippers.com>: Mar 12 08:48AM -0700 On 2018/03/11 8:25 PM, John Robertson wrote: >> couple of months.. Thanks, Lenny   > Best decision.   > John :-#)#   Further to this, one can purchase GFCI plugs that replace the original power cord plug and provide the same safety aspects as a GFCI outlet or circuit breaker. The advantage is you can add that to the power cord quickly...   https://store.leviton.com/collections/gfci/products/right-angle-automatic-reset-user-attachable-gfci-plug-15a-125v-16693?variant=18216174467   Do get one that is not counterfeit - Amazon/eBay are not reliable sources as the dealers there are completely unregulated and will sell you fakes as easily as real items. Go to a bricks and mortar shop if you want proper electrical safety.   John :-#)#   -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 (604)872-5757 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out."

tabbypurr@gmail.com: Mar 12 09:19AM -0700 > A friend of mine has a 120volt string of lights above his swimming pool. There is one 15 amp circuit for both the lighting and the pump motor circuit. This circuit is not protected by a GFCI outlet. The lights however are high enough so that no one can ever reach up and grab them while in the pool. We have had discussions about installing a GFCI on the pool circuit but as of the end of last Summer's swimming season it had not been done. One day last Summer I observed his kids in the pool shooting water blaster pistols in the air. Alarmed I quickly killed power to the lights. Naturally my concern was that someone in the pool shooting water up at the lights could be electrocuted. This brought about an interesting hypothetical discussion. What if the pool lighting circuit were connected through an isolation transformer. In theory then you should be able to grab each side of the secondary without being shocked right? I can't see how the motor could fail and become a shock hazard so I was more concerned about the lights.   > In any event I'm going to install a GFCI on his pool circuit for him before the start of swimming season which will be coming up in a couple of months. Thanks, Lenny   The only sensible option is to remove them and fit LV lights if wished. But to explore the hypothetical - or in your case real situation: 1. I am far from the only person to have been shocked by touching one terminal of an iso transformer. They aren't always set up to isolate, and there is interwinding capacitance too. And of course there are faulty transformers. 2. In an ideal world, an iso protects against contact with one terminal. It offers no protection whatever against contact with 2. 3. 120v lights can fall into the water 4. RCDs/GFCIs & isos interact to some extent in that if you put the RCD before the iso, the output is NOT RCD protected at all. If used together the RCd must go after the iso. 6. Rain-like water drops don't conduct electricity downward. You can stand under HV lines in the rain, the gaps between drops keep you safe. But this does NOT occur if you fire a water pistol up at it. 5. Remove the lights now. People in bodies of water are extremely vulnerable to shock.     NT

oldschool@tubes.com: Mar 11 03:52PM -0600 On Sun, 11 Mar 2018 08:42:37 -0000 (UTC), gregz <zekor@comcast.net> wrote:   >cleaners is Nathpha, or like Coleman Fuel. It dries slow enough to use >mechanical switch action to clean. For lube I like CRC 2-26.   >Greg   Aside from cost, I think Deoxit is the best spray to use. I'll continue to use Deoxit, but I do wish I could find a cheaper product for non-critical applications, such as the dashboard switches in cars. I used to use Radio Shack's contact cleaner and it was a good product, but now that R.S. is gone, I have not found any replacement. If anyone on here knows of a cheaper contact cleaner that is worthwhile, I'd like to hear about it. (and where ot buy it).   My personal opinion about WD-40 is not very good. PB Blaster is far superior for loosening rusted bolts and it lasts a lot longer too. I have not bought WD-40 in years, I have not found any real use for it. Yet it costs more than PB Blaster, even though it's an inferior product. WD-40 was more or less the first product of it's kind, and it gained a reputation for its name, so now the name is what sells it, except for people like myself who learned that it's not worth much. From what I have heard, WD-40 is mostly just Kerosene.

Phil Allison <pallison49@gmail.com>: Mar 11 06:33PM -0700 olds...@tubes.com wrote:   ------------------------- > >mechanical switch action to clean. For lube I like CRC 2-26.   > >Greg   > My personal opinion about WD-40 is not very good.   ** At least that sounds honest.     > I have not bought WD-40 in years, I have not found any real use for it.     ** Hard to find uses if you don't have any...     > WD-40 was more or less the first product of it's kind, and it gained a > reputation for its name, so now the name is what sells it,   ** A trusted name plus stocked damn near everywhere is the real reason.     > except for > people like myself who learned that it's not worth much.   ** Same as your personal opinions ....     > From what I > have heard, WD-40 is mostly just Kerosene.     ** Like that stupid one.         .... Phil

gregz <zekor@comcast.net>: Mar 12 08:31AM > reputation for its name, so now the name is what sells it, except for > people like myself who learned that it's not worth much. From what I > have heard, WD-40 is mostly just Kerosene.   At least PB Blaster actually displaces water instead of floating on water.   Greg

"pfjw@aol.com" <peterwieck33@gmail.com>: Mar 12 08:11AM -0700 https://www.wd40.com/files/pdf/msds-wd482671453.pdf   The above is the MSDS for WD40. And, yes, it is mostly ultra-refined kerosene. Track the CAS numbers to show that.   What it is not is Stoddard Solvent, although it has been accused of being that in the past.   http://www.sciencelab.com/msds.php?msdsId=9927610   Peter Wieck Melrose Park, PA

Fox's Mercantile <jdangus@att.net>: Mar 12 09:19AM -0500 On 2/13/18 9:46 AM, Fox's Mercantile wrote: > Anyone here running the Asterisk BX with the FreePBX GUI?   I found out a few things to make it work. you HAVE to assign a Direct Inbound Dialed number to make incoming calls work.   Magic Jack does NOT comply with AT&T/Bell ring standards so the FXO port never "hears" it ring.   And because I'm a stubborn bastard, I made a Cisco 7912 VoIP phone work with the system as well. So I can have a phone at the shop.     -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

Mike_Duffy <mqduffy001@bell.net>: Mar 11 09:17PM -0400 This is not really a 'repair' question; I'm just a bit curious about something and I suspect someone here might know about it.   My car (2012 Ford Escape) has as it's main gauges a tachometer & speedometer. Both are needles, and neither has a detente (needle rest) at zero. Despite lack of detentes, when the ignition is turned off, both needles go pretty quickly to the zero position without passing it.   About 18 seconds later, both needles 'dip' down (to about -500 RPM & -5 KPH) for a fraction of a second and then return to zero.   Why? If a door is open, that's about how long the interior lights take to start dimming.

Rheilly Phoull <rheilly@bigslong.com>: Mar 12 09:26AM +0800 On 12/03/2018 9:17 AM, Mike_Duffy wrote: > KPH) for a fraction of a second and then return to zero.   > Why? If a door is open, that's about how long the interior lights take to > start dimming.   Sounds a bit like a cap discharging after turn off.

gregz <zekor@comcast.net>: Mar 12 08:25AM > KPH) for a fraction of a second and then return to zero.   > Why? If a door is open, that's about how long the interior lights take to > start dimming.   Might be some kind of stepper motor reset ?   Greg

oldschool@tubes.com: Mar 11 04:00PM -0600 On Sat, 10 Mar 2018 22:59:20 -0500, Tim Schwartz <tim@bristolnj.com> wrote:     > If a second fuse blows right away, there are other issues in your VCR.   >Regards, >Tim   Since you dont know the cause of the blown fuse, and it's on a obsolete VCR, just take a common 3AG type of fuse, (of proper current rating), and put it into one of them cheap automotive fuse holders and put a small alligator clip on each end. Then just clip across the current fuse holder and plug in your VCR. If this fuse blows you have other problems and need to decide if this VCR is worth fixing.If it dont blow and the VCR works, either locatethe correct fuse, or just solder one of them automotive fuse holders across the one in the VCR.   Any fuse of the proper current and voltage will work. They just made those special oddball ones to make more money...

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